Planning Poker

Published March 18, 2023

Why Fibonacci for Story Points?

Fibonacci sequence is a sequence where each number is the sum of the previous two numbers as follows:

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89… That’s right, in a mathematically correct Fibonacci sequence the number ’1’ is repeated twice, however this detail is not useful for Agile estimation.

The world of Agile software development is an exciting one, filled with innovative methods and techniques designed to streamline the process and produce high-quality results. One such method is Agile estimation, a critical aspect that helps teams plan their work more efficiently. But have you ever considered why Fibonacci for story points could hold the key to better Agile estimation? Welcome to the intriguing world of Fibonacci Agile estimation.

Short Summary

  • The Fibonacci sequence is an invaluable tool for Agile estimation, providing precision and facilitating team collaboration.

  • It offers advantages such as increased accuracy, improved comparability and scalability of estimations.

  • Challenges can be addressed by customizing the sequence to suit teams’ needs while providing proper training on Weber’s law of noticeable differences.

The Power of the Fibonacci Sequence in Agile Estimation

A staircase resembling the Fibinacci spiral

The Fibonacci sequence, a series of numbers where each number is the sum of the two preceding ones, is a powerful tool for Agile estimation. Named after the Italian mathematician Leonardo Fibonacci, who introduced it to the Western world, it helps teams estimate with greater precision. Its exponential nature and distinct mathematical basis make it an ideal scale for estimating story points, the units used to measure the size and complexity of tasks in Agile projects.

Using the Fibonacci sequence for story point estimation offers numerous benefits. It not only heightens precision, but also facilitates team cooperation and comparability, making it an indispensable tool for Agile teams. But how exactly does this centuries-old mathematical principle fit into the modern world of Agile software development?

Mathematical Background

The traditional Fibonacci sequence has a unique mathematical background. Each number in the sequence is the sum of the two preceding ones, starting from 0 and 1. This exponential series of numbers has a distinct mathematical basis, making it suitable for Agile estimation. Interestingly, the sequence also helps to describe plant life growth patterns in nature, adding to its unique properties. In some cases, a modified Fibonacci sequence can be used to further refine these estimations and descriptions.

The Fibonacci sequence also follows. Weber’s law of just noticeable differences. This law states that the change in a stimulus that will be just noticeable is a constant ratio of the original stimulus. This makes the Fibonacci sequence an ideal tool for Agile estimation, as it captures the inherent uncertainty in estimating larger items, which are often more complex and have more unknowns.

Story Points and Fibonacci

In Agile estimation, story points represent the magnitude, complexity, and effort required to complete a user story. The Fibonacci sequence provides a suitable scale for gauging the “size” of tasks and user stories for future sprints, taking into account the assumed complexity, amount of effort needed, and risk or uncertainty.

The Fibonacci sequence facilitates relative sizing by enabling simpler comparison and estimation of task sizes. Because the relative size between two successive numbers in the Fibonacci sequence is greater than 60%, it makes it easier to differentiate between them. Also, the exponential nature of the Fibonacci scale facilitates comprehension of the assigned numbers by the whole team, promoting better collaboration and more accurate estimates.

Advantages of Using Fibonacci for Story Points

A shell resembling the Fibinacci spiral

Utilizing the Fibonacci sequence for story points offers a myriad of advantages. The sequence provides a process to gauge user stories in comparison to one another, assisting the team in comparing between two stories, and allowing the story to fit into the sequence. More importantly, it facilitates more precise estimations of the complexity of a task, helping teams to organize and manage their workload more effectively.

Involving the entire team in the estimation process offers the benefit of improved collaboration and comprehension of the task in question, as well as a heightened comprehension of the team’s abilities. All these benefits combined make the Fibonacci sequence a valuable tool in the Agile estimation toolbox.

Increased Accuracy

The Fibonacci sequence, with its unique properties, can help Agile teams achieve more accurate estimates. The team is encouraged to accurately estimate complexity and effort by assigning higher story point numbers. This leads to more reliable estimations. Employing Fibonacci for story points can prove useful in obtaining precise estimates, though the precision may vary depending on the team’s knowledge and comprehension of the scale.

The use of Fibonacci sequence in Agile estimation also heightens the precision of projections in project organization. This increased accuracy facilitates more precise estimations of the complexity of a task, which can assist the team in organizing and managing their workload more effectively.

Team Collaboration

Team collaboration is critical in Agile methodology. Implementing Fibonacci for story points encourages team collaboration and input from cross-functional teams, leading to more accurate estimations. It is of paramount importance to solicit the perspectives of each team member, as this will aid in attaining a more precise and realistic estimation of the effort required to achieve a user story.

Fibonacci Agile estimation necessitates the collective input of team members, thus providing a more precise, cooperative, and practical approach to project estimation. This not only helps in achieving more accurate estimates, but also promotes better understanding, cooperation, and communication within the team, making the fibonacci agile estimation work effectively.

Comparability and Scalability

The Fibonacci sequence also enables straightforward comparison and scalability of tasks, thus facilitating teams in their efforts to prioritize and allocate resources. Comparability guarantees that the estimates are uniform across diverse tasks, whereas scalability ascertains that the approach is able to manage rising volumes of work.

Indeed, the Fibonacci sequence can be utilized to compare tasks of varying sizes and complexity, as well as to scale tasks as the project advances. This feature of the Fibonacci sequence makes it a valuable tool for Agile teams in managing and planning their work.

Implementing Fibonacci Agile Estimation in Practice

A glass wall with stickers used for story estimates

While it is not compulsory to employ the Fibonacci sequence for story point estimations, its unique properties and benefits make it a popular choice among Agile teams. Agile teams can implement Fibonacci estimation using methods like Planning Poker or alternative techniques that still utilize the Fibonacci sequence.

The sequence and values of the Fibonacci sequence are easily distinguishable, thus allowing for estimation without the need to measure the objects, but rather by comparison. This shows how Agile estimation work can be improved using the Fibonacci sequence.

Planning Poker

Planning Poker is a popular method for implementing Fibonacci Agile estimation. It is a consensus-based, gamified technique for estimating, typically employed for timeboxing in Agile principles. Each team member is provided with a set of cards featuring point values, and they must come to a consensus on the point value for each task.

Planning Poker is a widely employed planning exercise in Agile estimation wherein team members cooperate and size stories using a Fibonacci sequence to assign a value to the epic/feature/story. It not only makes the process of estimation more interactive and engaging, but also ensures that all team members have an understanding of the task’s complexity and effort required.

Alternative Estimation Techniques

While planning poker is a popular method, there are also other alternative estimation techniques that Agile teams can use. These include Bucket System Estimation, T-shirt sizing, Large/Small method, Dot Voting, and affinity estimating. These techniques, while diverse in their approach, still utilize the Fibonacci sequence, ensuring that the core principles of Agile estimation are maintained.

For example, Bucket System Estimation involves dividing tasks into smaller buckets and assigning a point value to each bucket, facilitating teams to quickly assess the complexity of a task and allocate a point value to it. On the other hand, T-shirt sizing assigns tasks a size based on their complexity. Regardless of the technique used, the key is to maintain the core principles of the Fibonacci sequence.

Addressing Challenges and Modifying the Fibonacci Sequence

A flower resembling the Fibonacci spiral

Like any method, using the Fibonacci sequence for Agile estimation also comes with its own set of challenges. These include team members having varying interpretations of what each number in the Fibonacci sequence signifies in terms of effort or complexity, and a sense of compulsion to conform to the estimates of others.

However, these challenges can be addressed by providing proper training and guidance to team members and by customizing the Fibonacci sequence to better suit their needs. Customizing the Fibonacci sequence involves altering the initial numbers or employing alternative scales, while preserving the fundamental tenets of the sequence. This customization can facilitate comprehension of the intricacy of tasks, as well as promote team cooperation and communication.

Overcoming Common Challenges

Overcoming challenges such as confusion and complexity in estimation can be achieved by providing proper training and guidance to team members. Furnishing team members with appropriate instruction and direction can be beneficial in addressing the challenges of Fibonacci Agile Estimation.

Moreover, the understanding of Weber’s law of noticeable differences can help in this aspect. As the law states that the change in a stimulus that will be just noticeable is a constant ratio of the original stimulus, it helps in understanding the exponential nature of the Fibonacci sequence and its suitability in Agile estimation.

Customizing the Sequence

A software engineering team discussing the project planning

Customizing the Fibonacci sequence, also known as the modified Fibonacci, can be a powerful tool for Agile teams. By choosing to use the Fibonacci sequence, teams can alter the initial numbers or employ alternative scales, while preserving the fundamental tenets of the sequence. For instance, teams can include additional numbers such as 0, 1/2, or 1/4 to provide greater precision and more accurately reflect the complexity of tasks.

Upholding the fundamental principles of the Fibonacci sequence is essential in order to guarantee the sequence’s consistency and dependability. Even with these modifications, the Fibonacci sequence remains a powerful and versatile tool for Agile estimation.

Real-World Examples of Fibonacci Agile Estimation

The power of Fibonacci Agile estimation is not just theoretical; it has been proven time and again in real-world applications. Many companies that employ Agile methodology often utilize the Fibonacci sequence as a scoring scale when estimating the effort of Agile development tasks. This sequence is employed to assign numbers to story points, thereby aiding teams in sizing stories that possess a discernible value.

Take the example of Parabol’s Sprint Poker product, which uses the Fibonacci sequence as the default numerical set for playing cards. This real-world implementation of Fibonacci Agile estimation showcases its effectiveness and benefits for Agile teams, proving its value as a powerful estimation method.


The Fibonacci sequence has proven to be a powerful tool for Agile estimation. Its unique properties, including its exponential nature and ability to represent story points effectively, make it a popular choice among Agile teams. Through methods like Planning Poker and other alternative techniques, Agile teams can implement Fibonacci Agile estimation effectively in their projects.

The Fibonacci sequence not only elevates the accuracy of estimates, but also promotes team collaboration and comparability of tasks. While it does come with certain challenges, these can be effectively addressed through proper training and customization of the sequence. With its real-world effectiveness and numerous benefits, Fibonacci Agile estimation truly stands as an invaluable tool in the Agile toolkit.

Frequently Asked Questions

Why is Fibonacci series used for story estimation?

Fibonacci’s sequence of distinct values enables teams to accurately compare between two stories and determine their relative sizes, allowing them to refine the story by removing uncertainty.

This helps teams better understand the scope of the story and make more informed decisions about how to approach it. It also allows them to break down the story into smaller, more manageable chunks, making it easier to work on.

Can a Fibonacci sequence be used for story points?

Yes, the Fibonacci sequence can be used for story points as it is a popular scoring scale used in agile development. Each number is the sum of the previous two numbers in the series which follows 0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89….

How do you use the Fibonacci scale?

The Fibonacci scale is commonly used to estimate agile story points, with each number in the sequence being the sum of the previous two. 0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89 and so on are the numbers in the Fibonacci sequence that you can use for scoring.

This scale is a great way to quickly estimate the complexity of a story and assign it a point value. It is also useful for comparing stories of different sizes and complexity. By using the Fibonacci scale, you can quickly use the Fibonacci scale.

Why do we use Fibonacci series in Scrum?

The choice of Fibonacci series in Scrum comes down to its knack for swift and instinctive story point estimation. It fits seamlessly into the unpredictable landscape of software development, making planning and resource allocation during Sprints a more intuitive process.

Why does Jira use Fibonacci sequence?

Jira integrates the Fibonacci sequence for story points, enhancing flexibility in Agile teams. The non-linear nature allows nuanced representation of task complexity, fostering collaboration and precision in estimating work effort for effective project management.

Why do we need the Fibonacci sequence?

The Fibonacci sequence is crucial in Agile for its non-linear progression, addressing challenges in estimating task complexity. It facilitates relative sizing, enabling effective comparison and collaboration, offering increased accuracy, comparability, and scalability for managing Agile project workloads.

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